Vitamin C

Vitamin C has been in the public eye for a long time. Even before its discovery in 1932, nutrition experts recognized that something in citrus fruits could prevent scurvy, a disease that killed as many as two million sailors between 1500 and 1800. (1) In the 1970s, Chemistry and Peace Nobel laureate Linus Pauling promoted daily megadoses of vitamin C (the amount in 12 to 24 oranges) as a way to prevent colds and some chronic diseases.

There’s no question that vitamin C plays a role in controlling infections. It’s also a powerful antioxidant that can neutralize harmful free radicals, and it helps make collagen, a tissue needed for healthy bones, teeth, gums, and blood vessels. (2) The question is, do you need lots of vitamin C to keep you healthy?

No. Vitamin C’s cold-fighting potential certainly hasn’t panned out. Small trials suggest that the amount of vitamin C in a typical multivitamin taken at the start of a cold might ease symptoms, but for the average person, there’s no evidence that megadoses make a difference, or that they prevent colds. (3) Studies of vitamin C supplements and heart disease, cancer, and eye diseases such as cataract and macular degeneration also show no clear patterns.

References

1.Carpenter KJ. The history of scurvy and vitamin C. Cambridge: Cambridge University Press, 1986.

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How Much Do I Need? Vitamin C

The Institute of Medicine's current recommended dietary intake for vitamin C (also called ascorbic acid) is 90 milligrams for men and 75 milligrams for women (add an extra 35 milligrams for smokers). The upper limit for vitamin C is set at 2 grams per day. There's no good evidence that megadoses of vitamin C improve health. As the evidence continues to unfold, 200 to 300 milligrams of vitamin C a day appears to be a good target. This is easy to hit with a good diet and a standard multivitamin.

Food sources:

Excellent food sources of vitamin C are citrus fruits or citrus juices, berries, green and red peppers, tomatoes, broccoli, and spinach. Many breakfast cereals are also fortified with vitamin C.